Webb observes menagerie of lensed galaxies behind ‘El Gordo’ cluster

Peering at a galaxy cluster known as “El Gordo,” the James Webb Space Telescope has spotted a host of background galaxies, magnified, warped and distorted by gravitational lensing to produce a menagerie of never-before-seen star swarms. El Gordo includes hundreds of galaxies that existed when the universe was 6.2 billion years old. The most striking feature, perhaps, is a bright arc of red at upper right nicknamed El Anzuelo, or The Fishhook, a lensed galaxy dating back 10.6 billion years (labeled B in the second image below). Observers were able to correct the distortions to find the background galaxy is disk shaped but only about 26,000 light years in diameter. They were also able to determine star formation was slowing down in a process known as quenching. Another intriguing feature is a long thin line at left of center known as La Flaca, or The Thin One (labeled A in the second image below). It’s another lensed galaxy some 11 billion light years away. Numerous other gravitationally magnified galaxies are also visible. Click on the image below for a zoomed-in version.

The “El Gordo” galaxy cluster as seen by the James Webb Space Telescope. Image: NASA, ESA, CSA; image processing: Alyssa Pagan (STScI), Jake Summers (ASU), Jordan C. J. D’Silva (UWA), Anton M. Koekemoer (STScI), Aaron Robotham (UWA), Rogier Windhorst (ASU)
Image: NASA, ESA, CSA; image processing: Alyssa Pagan (STScI), Jake Summers (ASU), Jordan C. J. D’Silva (UWA), Anton M. Koekemoer (STScI), Aaron Robotham (UWA), Rogier Windhorst (ASU)